Question: $\dfrac{20}{100} + \dfrac{15}{10} = {?}$
Answer: The fractions must have the same denominator before you can add them. Rewrite $\dfrac{15}{10}$ as $\dfrac{150}{100}$ $\dfrac{20}{100} + \dfrac{150}{100} = {?}$ $ = \dfrac{170}{100}$